Surgical fastener with predetermined resorption rate

ABSTRACT

A resorbable screw fastener and a method of firing with an applicator capable of applying a surgical fastener to tissue in order to form tissue connection to secure objects to tissue, the fastener including a body portion having a helical thread, a head portion disposed at the proximal end of the body portion. The resorbable screw fastener is 100% resorbed in vivo during a period of time ranging from about 14 days to about one year after implantation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of, and claims the benefit of andpriority to, U.S. patent application Ser. No. 13/190,669 (U.S. PatentPublication Application No. 2011-0282401), filed on Jul. 26, 2011,which, in turn, is a Continuation of, and claims the benefit of andpriority to, U.S. patent application Ser. No. 11/113,879 (U.S. Pat. No.8,002,811), filed on Apr. 25, 2005, which, in turn, is aContinuation-in-Part of, and claims the benefit of and priority to,International Application PCT/US04/18702, filed on Jun. 14, 2004, which,in turn, claims the benefit and priority to U.S. Provisional PatentApplication Ser. No. 60/478,352 filed on Jun. 13, 2003, the disclosuresof each of which are hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Technical Field

The present disclosure relates generally to surgical fasteners, surgicalfastener appliers and methods for connecting body tissue and, moreparticularly, to bioresorbable screw fasteners, screw fastener appliers,and methods of using the screw fastener applier to fire multipleresorbable screw fasteners to a target surgical site.

2. Description of Related Art

Surgical fasteners are used to eliminate the need for suturing, which isoften time consuming and inconvenient. Surgical fasteners accomplish inseconds what would have taken many minutes to accomplish by suturing,thus reducing operating time and trauma to the patient. In hernia repairprocedures, for example, the weakened area of the abdominal wall may bereinforced with a synthetic mesh or by suturing the abdominal tissue. Insuch an instance, a surgical fastener may be used, in lieu of, or inaddition to, a surgical suture to fix the position of the mesh.

For example, in some cases titanium staples are utilized to retain themesh in place. These staples thus become permanent residents in the bodycavity. Other fasteners may be utilized which are made of bioresorbablematerials, many of which, however, remain in vivo for extended periodsof time. A disadvantage of permanent metal staples and/or those thatremain in the body for an extended period of time is the possibility ofthe formation of excessive scar tissue (adhesions), which in turn cancause further patient complications and hinder future surgicalprocedures. In addition, these permanent or long-term staples may beassociated with increased discomfort to the patient over time as aresult of the hernia repair procedure.

In view of the widespread use of surgical fasteners, a continuing needexists for improved surgical fasteners, surgical fastener appliers, andmethods of applying the surgical fasteners.

SUMMARY

Accordingly, the present disclosure relates to a resorbable fastener toform tissue connections. Because it is resorbable, use of the fastenerof the present disclosure reduces the amount of foreign material in thepatient's body, thereby minimizing adhesion formation and reducingfastener-associated long-term discomfort to the patient. The fastener ofthe present disclosure retains sufficient strength for enough time topermit the healing and/or in-growth of tissue at the repair site, afterwhich time it is completely resorbed by the body. The fastener of thepresent disclosure can be 100% resorbed in vivo during a period of timeranging from about 14 days to about one year after implantation.

In one embodiment, the fastener of the present disclosure has a shearstrength of about 3.5 pounds to about 5.5 pounds during a period of timeranging from the time of implantation in vivo to about one week afterimplantation, a shear strength ranging from about 0.5 pounds to about4.2 pounds during a period of time ranging from about one week to about1.5 weeks after implantation, and a shear strength of about 0 poundsabout one year after implantation.

In one embodiment, the resorbable fastener of the present disclosure isa screw fastener which possesses a head configuration which permits theuse of a combined rotational force and linear force to facilitateinsertion. The resorbable screw fastener is tacked into body tissue toform tissue connection to secure objects such as a mesh material totissue.

In another embodiment, the resorbable fastener is a screw fastener whichincludes a body portion having a helical thread, a head portion disposedat the proximal end of the body portion and a blunt end at a distalportion of the body portion. The head portion includes a driverreceiving configuration on its outer diameter, said driver receivingconfiguration is used to transmit both linear and rotational forces inorder to drive the resorbable screw fastener. The body portion of thebioresorbable fastener is threaded, with the spacing between adjacentthreads being augmented to provide a wider pitch. In addition, thethread's outer diameter is enlarged creating substantially more land,giving the resorbable screw fastener greater stability and preventingdislodgement from the body tissue. The resorbable screw fastenerincludes a cannulated center lumen with an opening extending from thehead portion through the longitudinal length of the body portion of theresorbable fastener. The head portion may also include a flat segment,which may further extend to the outside of the threads.

In other embodiments, the fastener of the present disclosure may possessa helical configuration. In yet another embodiment, the fastener of thepresent disclosure may be a clip.

Other features and advantages of the present invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, which illustrate, by way of example, theprincipals of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will be better appreciated byreference to the drawings wherein:

FIG. 1 is a perspective view of a resorbable fastener in accordance withan embodiment of the present disclosure;

FIG. 2 is another perspective view of the resorbable screw fastener ofFIG. 1;

FIG. 3 is a longitudinal cross-sectional view of the resorbable screwfastener of FIG. 1 taken along line 3-3 of FIG. 1;

FIG. 4 is an orthogonal top view of the resorbable screw fastener ofFIG. 3;

FIG. 5 is a perspective view of an embodiment of a screw fastenerapplier according to an embodiment of the present disclosure;

FIG. 6 is a side view, with a housing half removed, of the housingportion of the screw fastener applier of FIG. 5 while in an initialposition;

FIG. 7 is a perspective view of a distal end of the screw fastenerapplier of FIG. 5;

FIG. 8 is a perspective partial cross-sectional cut-away view of thedistal end of the screw fastener applier of FIGS. 5 and 6;

FIGS. 9-17 are partial cross-sectional or cut-away side elevationalviews of the distal end of the screw fastener applier of FIGS. 5-8,illustrating a series of operational steps of the screw fastener applierfor driving the resorbable screw fastener of FIGS. 1-4 into the targetsurgical site;

FIG. 18 is a perspective view of another embodiment of a resorbablescrew fastener of the present disclosure;

FIG. 18A is a longitudinal cross-sectional view of the resorbable screwfastener of FIG. 18 taken along line 18A-18A of FIG. 18;

FIG. 18B is a top view of the resorbable screw fastener of FIGS. 18 and18A;

FIG. 19 is a perspective view of a distal end of a screw fastenerapplier according to another embodiment of the present disclosure, withan end effector operatively secured thereto;

FIG. 20 is a perspective view of the distal end of the screw fastenerapplier of FIG. 19, with the end effector separated or disconnectedtherefrom;

FIG. 21 is a perspective view of the assembled cam spiral sub-assembly,inner tube sub-assembly and outer tube of the end effector according tothe present disclosure;

FIG. 22 is a perspective view of a cam spiral sub-assembly of the endeffector of FIG. 21 with the outer tube and inner tube sub-assemblyremoved therefrom;

FIG. 23 is a further perspective view of the cam spiral sub-assembly ofFIG. 22;

FIG. 24 is a perspective view of the cam spiral sub-assembly of FIGS. 22and 23, with a pusher and feed spring shown operatively associatedtherewith;

FIG. 25 is a perspective view of the cam spiral sub-assembly of FIG. 24,illustrating a screw fastener operatively associated therewith;

FIG. 26 is a perspective view of the cam spiral sub-assembly of FIGS. 24and 25, with a pair of screw fasteners operatively associated therewith;

FIG. 27 is a perspective view of the cam spiral sub-assembly of FIGS.24-26, with at least three screw fasteners operatively associatedtherewith;

FIG. 28 is a perspective view of the inner tube sub-assembly of the endeffector of FIGS. 21 and 28;

FIG. 29 is a perspective view of the cam spiral sub-assembly of FIG. 27operatively disposed within the inner tube sub-assembly of FIG. 28,while in a first position;

FIG. 30 is a perspective view of the cam spiral sub-assembly and innertube sub-assembly of FIG. 29, while in a second position;

FIG. 31 is a perspective view of the cam spiral sub-assembly of FIG. 27,while in the second position of FIG. 30;

FIGS. 32-36 illustrate a series of operational steps of the surgicalfastener applier including the end effector of FIGS. 19-31 for drivingthe resorbable screw fastener of FIGS. 18, 18A and 18B into the targetsurgical site;

FIG. 37 is a cross-sectional side perspective view of a resorbable screwfastener according to a further embodiment of the present disclosure;

FIG. 38 is a longitudinal cross-sectional view of the resorbable screwfastener of FIG. 37 taken along line 38-38 of FIG. 38;

FIG. 39 is a graph depicting the strength-loss profile of a resorbablefastener of the present disclosure compared with a commerciallyavailable fastener;

FIG. 40 is a graph depicting tensile test results of a fastener of thepresent disclosure affixed to a synthetic dog bone made of aglycolide-lactide copolymer;

FIG. 41 is a graph depicting shear test results of a fastener of thepresent disclosure affixed to a synthetic dog bone made of aglycolide-lactide copolymer;

FIG. 42 depicts a perspective view of a resorbable fastener of thepresent disclosure, illustrating a side view of a helical fastener;

FIG. 42A depicts another perspective view of a resorbable fastener ofthe present disclosure, illustrating an end view of the helicalfastener;

FIG. 42B depicts a schematic view of a resorbable fastener of thepresent disclosure, illustrating a substantially collapsed helicalfastener with a relatively small gap that has been partially insertedinto tissue;

FIG. 42C depicts a schematic view of a resorbable fastener of thepresent disclosure, illustrating the helical fastener depicted in FIG.42B completely inserted into tissue;

FIG. 42D depicts a schematic view of a resorbable fastener of thepresent disclosure, illustrating a substantially collapsed helicalfastener with a relatively large gap that has been partially insertedinto the tissue;

FIG. 42E depicts a schematic view of a resorbable fastener of thepresent disclosure, illustrating the helical fastener depicted in FIG.42D completely inserted into tissue;

FIG. 42F depicts a perspective view of another embodiment of aresorbable fastener of the present disclosure, illustrating an end viewof the helical fastener;

FIG. 43 depicts a perspective view of another embodiment of a resorbablefastener of the present disclosure, illustrating a double helicalfastener;

FIG. 43A is a front view of the double helical fastener of FIG. 43;

FIG. 43B is side view of the double helical fastener of FIG. 43;

FIG. 43C is a top view of the double helical fastener of FIG. 43;

FIG. 44 is a perspective view of yet another embodiment of a resorbablefastener of the present disclosure, illustrating another design of adouble helical fastener;

FIG. 44A is a front view of the double helical fastener of FIG. 44;

FIG. 44B is a side view of the double helical fastener of FIG. 44;

FIG. 44C is a top view of the double helical fastener of FIG. 44;

FIG. 45 is a perspective view of another resorbable fastener of thepresent disclosure, illustrating a helical fastener with a central post;

FIG. 46 shows a plan view of a resorbable fastener having a clipconfiguration according to the present disclosure;

FIGS. 47 and 48 show another embodiment of a resorbable fastener havinga clip configuration according to the present disclosure; FIG. 47 is aplan view, on an enlarged scale,

FIG. 48 is a side view;

FIG. 49 is a graph depicting the reduction in the maximum load for afastener of the present disclosure made of a glycolide-lactide copolymerthat had been subjected to heating; and

FIG. 50 is a graph depicting the reduction in the maximum load for afastener of the present disclosure made of a glycolide-lactide copolymertreated by exposure to a low-temperature gas plasma at a pressuresubstantially below atmospheric.

DETAILED DESCRIPTION OF THE EMBODIMENTS

A resorbable surgical fastener is provided which may be utilized toattach an object to tissue or to attach tissue to tissue, such as tissueto ligament. The resorbable surgical fastener permits tissue healing andin-growth and degrades in vivo after sufficient healing and/or in-growthhas occurred, but prior to the formation of adhesions, therebyminimizing any pain or discomfort which can occur through the placementof permanent surgical fasteners or surgical fasteners which remain invivo for extended periods of time.

Referring now in detail to the figures, which are included for purposesof illustration and not by way of limitation, a resorbable fastener ofthe present disclosure is illustrated in FIGS. 1-4, and is designatedgenerally as resorbable screw fastener 10.

The presently disclosed embodiments of resorbable screw fastener 10contemplate the insertion of a resorbable screw fastener through atrocar into various tissue types using minimal application of force.Tissue typically wicks into the mesh in about 7-10 days, meaning thatthe fastener must maintain a certain structural integrity for at leastthat amount of time. In some embodiments, resorbable screw fastener 10may be constructed so as to maintain its structural strength by about80% for about 10-21 days. Thereafter, the tissue will grow into the meshand the resorbable screw fastener 10 will be resorbed by the body at afixed rate leaving in place only the mesh.

Although the specific focus of this disclosure will be on a laparoscopichernia repair, it will be noted that hernia repair is merelyrepresentative of a type of surgical procedure wherein resorbable screwfastener 10 can be utilized. Other such procedures include vaginalprolapse repair, use of an anchored mesh for urinary incontinencerepair, etc.

In the following description, as is traditional, the term “proximal”refers to the portion of the screw, applier or instrument closest to theoperator, while the term “distal” refers to the portion of the screw,applier or instrument remote from the operator.

Referring now to FIGS. 1-4, resorbable screw fastener 10 includes twomain components, namely a body portion 12 defining a longitudinal axis“X” and a substantially circular head portion 14 disposed on a proximalend of body portion 12. Resorbable screw fastener 10 further includes acentral cannulated opening or lumen 18 extending along the longitudinal“X” axis of body portion 12 and head portion 14 for receiving a matingpart therein, as will be described in greater detailed below. In oneembodiment, cannulated lumen 18 has a hexagonal traverse cross-sectionalprofile (not shown). Alternatively, it is envisioned that cannulatedlumen 18 may have a circular, rectangular or triangular traversecross-sectional profile.

Body portion 12 includes a helical thread 16 extending along a lengththereof, and may also include a truncated or blunt distal end 20.Further body portion 12 includes a center shaft 13 extending along alength thereof. Center shaft 13 and/or may have a constant outerdistance D1 and D2, or may taper from a larger proximal end to a smallerdistal end.

In one embodiment, head portion 14 has a distance “D” (of about 3.51 mm)which is approximately 54% of an overall length “L” (of about 6.5278 mm)of screw fastener 10. Additionally, body portion 12 has a length “L1”which is approximately 70-80% of the overall length “L” of screwfastener 10. In another embodiment, length “L1” is about 77% of theoverall length “L”. For example, head portion 14 may have a height orlength “L2” of about 1.5 mm and body portion 12 may have a length “L1”of about 5.0 mm. In yet another embodiment, distance “D” of head portion14 is substantially equal to an outer distance “D1” of body portion 12and helical thread 16.

The dimensions and physical characteristics of resorbable screw fastener10 are selected to insure a secure attachment of screw fastener 10 totissue. Similarly, the dimensions and physical characteristics ofapplicator 100 (FIG. 5) utilized to dispense screw fastener 10 intotissue are dependent upon the particular application.

With continued reference to FIGS. 1-4, head portion 14 includes driverreceiving recesses or structure, in the form of slots 28, formed in anouter radial surface of head portion 14. Slots 28 are configured totransmit torque to screw fastener 10. In one embodiment, a pair ofdiametrically opposed slots 28 are formed in head portion 14.Additionally, each slot 28 may be tapered at an angle toward thelongitudinal “X” axis extending distally from a proximal surface headportion 14. The taper of slots 28 helps to facilitates rotation anddriving of screw fastener 10. Alternatively or additionally, it isenvisioned that a torque transmitting feature may be provided on slots28, in the form of shoulders 26, or on the centrally cannulated opening18, in the form of a keyed surface (not shown). As described herein, thetorque transmitting feature allows for screw fastener 10 to be rotated.

With particular reference to FIG. 3, body portion 12 includes a singlecontinuous helical thread 16 thereon. Thread 16 includes an outerdistance “D1” which is substantially enlarged as compared to an innerdistance “D2” thereof. Having a substantially enlarged outer distance“D1” as compared to inner distance “D2” enables the tissue to more fullyand intimately adhere to the surface of screw fastener 10, consequentlyreducing instances of dislodgement of screw fastener 10. Thread 16 has apitch “P” (as seen in FIG. 1) between adjacent individual threads.

Thread 16 is also desirably tapered at both a distal lead-in 16 a and aproximal run-out 16 b. A space or gap 16 c is provided between proximalthread run-out 16 b and a distal surface of head portion 14. Gap 16 callows for the surgical mesh to rest therein. It is envisioned that thepitch of thread 16 may be larger or smaller depending on the particularsurgical procedure. Additionally, the cross-sectional shape of thread 16may be triangular, rectangular, etc.

As seen in FIGS. 1-4, screw fastener 10 may include at least one pair(three pairs shown) of diametrically opposed planer or flattenedsurfaces 22 formed in the outer radial surface of head portion 14 andhelical thread 16. Each planar surface 22 may additionally be in radialregistration with a respective slot 28. Planar surface 22 extendsdistally from head portion 14 to helical thread 16 of body portion 12and substantially along the entire length of body portion 12. Planarsurface 22 is provided for orientation of screw fastener 10 insidefastener applier 100, as will be described in detail below. It isenvisioned that other features may be provided for orientation of screwfastener 10 inside fastener applier 100.

Screw fasteners 10 may be fabricated from any bioresorbable polymer orcopolymer known to those skilled in the art, so long as the polymerutilized has sufficient strength and possesses the necessary mechanicalproperties to permit its formation into a screw fastener of the presentdisclosure and the application thereof. Suitable polymers which may beutilized to form screw fasteners 10 include, but are not limited to,trimethylene carbonate, caprolactone, dioxanone, glycolic acid, lacticacid, glycolide, lactide, homopolymers thereof, copolymers thereof, andcombinations thereof.

In one embodiment, the fastener of the present disclosure may be made ofa glycolide-lactide copolymer. The amount of glycolide can range fromabout 10% (mole percent) to about 50% of the glycolide-lactide copolymerutilized to form the fastener of the present disclosure, typically fromabout 15% to about 45% of the glycolide-lactide copolymer. The amount oflactide can thus range from about 90% (mole percent) to about 50% of theglycolide-lactide copolymer utilized to form the fastener of the presentdisclosure, typically from about 85% to about 55% of theglycolide-lactide copolymer. In another embodiment, a fastener of thepresent disclosure may be a homopolymer of glycolic acid (100%polyglycolide).

In yet another embodiment, the fastener of the present disclosure may bemade of a glycolide-trimethylene carbonate copolymer. The amount ofglycolide can range from about 50% (mole percent) to about 90% of theglycolide-trimethylene carbonate copolymer utilized to form the fastenerof the present disclosure, typically from about 55% to about 70% of theglycolide-trimethylene carbonate copolymer. The amount of trimethylenecarbonate can thus range from about 10% (mole percent) to about 50% ofthe glycolide-trimethylene carbonate copolymer utilized to form thefastener of the present disclosure, typically from about 30% to about45% of the glycolide-trimethylene carbonate copolymer.

In other embodiments, screw fastener 10 may be made of polyglycolic acidor poly-glycolide (PGA) and/or polylactic acid (PLA), any otherbiocompatible implantable material, or any combinations thereof.

In some particularly useful embodiments screw fastener 10 may befabricated from a medical bioresorbable copolymer material including,but not limited to, a polyglycolide -co-L-lactide at a ratio of 18/82, apolyglycolide-co-L-lactide at a ratio of 42/58, or apolyglycolide-co-trimethylene carbonate at a ratio of 63/37.

The copolymers described herein can be produced utilizing methods knownto those skilled in the art. In some embodiments, the polymerization mayinclude use of a catalyst (e.g., stannous octoate) and/or an initiator(e.g., glycolic acid). In addition, in some instances additives and/orfillers may be added to the screw fasteners of the present disclosure.For example, screw fastener 10, or a portion thereof, may be coated witha biocompatible material such as parylene, that may also be lubricious,which provides for easier delivery of screw fastener 10 into tissue. Inaddition, a parylene coating may extend the resorption time of screwfastener 10. Typically, such screw fasteners 10 are formed using aninjection molding process as would be understood by one skilled in theart.

Screw fasteners 10 fabricated from a bioresorbable material inaccordance with the present disclosure maintain their structuralintegrity after implantation (e.g., about 80% of original strength) fora predetermined period of time, depending on the characteristics of theparticular copolymer used. Such characteristics include, for example,the components of the copolymer, including both the monomers utilized toform the copolymer and any additives thereto, as well as the processingconditions (e.g., rate of copolymerization reaction, temperature forreaction, pressure, etc.), and any further treatment of the resultingcopolymers, i.e., sterilization, etc.

Screw fasteners 10 of the present disclosure typically maintain theirstructural integrity, i.e., 80% of their original strength, afterimplantation for periods of time ranging approximately from about 5 daysto about 52 weeks, typically from about 7 days to about 90 days, moretypically from about 10 days to about 21 days.

The screw fasteners 10 of the present disclosure are typically resorbedin vivo within one year of implantation in a patient's body. As withmaintenance of the structural integrity of the screw fastener discussedabove, the rate of resorption of the screw fasteners may also depend onthe characteristics of the particular copolymer used (including both themonomers utilized to form the copolymer and any additives thereto), aswell as the processing conditions (e.g., rate of copolymerizationreaction, temperature for reaction, pressure, etc.), and any furthertreatment of the resulting copolymers, i.e., sterilization, etc. Asnoted above, the addition of a parylene coating may, in someembodiments, extend the resorption time of screw fastener 10 so that ittakes a longer time to be resorbed by a subject patient's body.

Typically, the screw fasteners 10 of the present disclosure are not 100%resorbed before the expiration of one week post-implantation in asubject, but are 100% resorbed by the body of a subject patient afterimplantation within one year, typically less than 9 months, moretypically less than 6 months, in some cases less than 3 months. Thus, insome embodiments, the screw fastener 10 may be 100% resorbed in asubject patient within about 14 days to about one year afterimplantation of screw fastener 10, typically from about 21 days to about3 months after implantation, more typically from about 28 days to about2 months after implantation.

It has been found that repair of, for instance, a hernia requires thatthe mesh be anchored using fasteners capable of withstanding certainforces exerted upon it, as for instance that may be experienced when apatient coughs or lifts a heavy load. For this reason, the fastener ofthe present disclosure has been designed to withstand a tensile load offrom about 0 to about 10 pounds of force, typically from about 2 toabout 8 pounds of force upon implantation, and a shear load of about 0to about 5.5 pounds of force, typically from about 3.5 to about 4.4pounds of force upon implantation.

Conversely, it has also been found that fasteners capable ofwithstanding such forces for indefinite periods of time result in theformation of adhesions in a patient and increased pain and patientdiscomfort. The fasteners of the present disclosure have therefore beendesigned with these requirements of strength while requiring that thefastener be totally resorbed by the body within a certain period of timeso as to minimize such adverse implications to the patient.

In one particularly useful embodiment, fasteners of the presentdisclosure are capable of maintaining a shear load for a desired periodof time, after which the shear load begins to decrease. As used herein,the term “shear load” is synonymous with “shear strength” and the twomay be used interchangeably. From the time of implantation in vivo toabout one week after implantation, the fasteners of the presentdisclosure generally possess a shear strength ranging from about 3.5pounds to about 5.5 pounds, typically from about 3.8 pounds to about 4.2pounds. From about 1 week to about 1.5 weeks post-implantation, theshear strength ranges from about 0.5 pounds to about 4.2 pounds,typically from about 0.65 pounds to about 2.5 pounds, more typicallyfrom about 0.75 pounds to about 1.5 pounds and, eventually, a fastenerof the present disclosure will have a shear strength of about 0 poundsabout one year post-implantation. In some embodiments the fastener ofthe present disclosure may have a shear strength of about 0 pounds at atime ranging from about 3 weeks to about 12 weeks post-implantation,typically at a time of from about 4 weeks to about 8 weekspost-implantation.

FIG. 39 is a graph comparing the loss of strength of one suture fastenerof the present disclosure with a commercially available fixation device(a PARIEFIX® mesh/fixation device commercially available from SofradimCorp. (Wrentham, Mass.)). The fastener was made of a 18/82polyglycolide-co-L-lactide copolymer. As can be seen in FIG. 39, in thisembodiment, the fastener of the present disclosure should have aninitial strength capable of withstanding at least 3.5 pounds of force inany direction upon implantation (at time=0), which remains for about 7days, at which point the fastener may begin to lose strength. At thatpoint, the resorption of the screw fastener 10 of the present disclosurewill continue until it is 100% resorbed by the body. As noted above, thescrew fastener 10 of the present disclosure is typically 100% resorbedin less than one year after implantation. To the contrary, the PARIEFIX®mesh/fixation device maintains an ability to withstand about 5 pounds offorce for more than one year, which is not necessary in the repair of ahernia utilizing a hernia mesh and requires the surgical fastener toremain in vivo for an extended period of time, i.e., at least for morethan one year, which could lead to the formation of adhesions in apatient and increased pain and patient discomfort.

ASME dogbones and fasteners were created out of 18/82polyglycolide-co-L-lactide copolymer. Under an Instron load, at day zerothe dogbone was either subjected to a tensile load or the fastener wassubjected to a shear load. The dogbones and fasteners tested after dayzero were placed in a saline bath simulating an in vivo environment.Depending on the day intervals, subsequent dogbones and fasteners wereremoved from the saline bath and tested the same way as on day zero.FIG. 40 shows a graph of tensile results for a synthetic dog bone madeof an 18/82 polyglycolide-co-L-lactide copolymer. As can be seen in FIG.40, the synthetic dog bone had a peak load of about 25 lbs. uponplacement in the saline bath, which corresponded to implantation, whichdecreased to below 10 pounds at 28 days post-implantation, i.e., afterplacement in the bath. The fastener made with this same material wassubjected to shear testing. FIG. 41 is a graph showing the shear testresults. As can be seen in FIG. 41, the average load for these fastenersranged from slightly more than 2.50 kgf (5.51 lbs) upon implantation anddecreased to below 1.50 kgf (3.31 lbs) at 18 days post-implantation.

In some embodiments, it may be desirable to treat the fasteners of thepresent disclosure to control their rate of degradation. For example, insome embodiments it may be desirable to heat the fasteners of thepresent disclosure to obtain the desired rate of resorption. The heatingof the fastener may also remove monomers remaining in the polymersutilized to form the fasteners. Suitable temperature for heating thefasteners can range from about 100° C. to about 160° C., typically fromabout 120° C. to about 143° C., for a period of time ranging from about2 hours to about 24 hours, typically from about 8 hours to about 16hours. In some embodiments, the heating may take place in a vacuum.

FIG. 49 is a graph depicting the maximum load for fasteners of thepresent disclosure that were subjected to heat treatment. The fastenerswere made of a homopolymer of glycolic acid (100% polyglycolide).Fasteners were heat treated in a vacuum to 143° C. for 12 hours todetermine the absorption rate for the desired fastener form. A shearforce test was conducted after the fasteners were placed in a salinebath simulating an in vivo environment, the results of which are setforth in FIG. 49. As can be seen in FIG. 49, the day zero strength was2.50 kgf (5.51 lbs), while the day thirteen strength was 1.66 kgf (3.66lbs). At day fourteen and subsequent days, the strength dropped sharply.

In other embodiments, the rate of degradation of the fasteners of thepresent disclosure may be controlled by exposing them to alow-temperature gas plasma at a pressure substantially below atmosphericfor a sufficient period of time. Such a method of treatment is known andincludes, for example, the treatment disclosed in U.S. Pat. No.5,236,563, the entire disclosure of which is incorporated by referenceherein. Typically, the surface treatment is limited in time to treat thesurface layer to a depth from about 100 to about 1500 Angstroms, therebyproducing a cross-linked polymer layer that will not adversely affectthe desired handling qualities of the polymer.

Fasteners treated with such a gas plasma have a thin surface layerpossessing additional cross-links of the polymer and/or an increase inthe surface hydrophobicity of the polymer, which results from a reactionof the polymer with surface-modifying components, typically halogenssuch as fluoride ions. The treated polymers possess desirabledegradation characteristics including wettability and fluid diffusivity,so as to modulate the hydrolyzation rate of the polymer utilized to makethe fastener of the present disclosure.

FIG. 50 is a graph depicting the maximum load for a fastener of thepresent disclosure that was subjected to a low-temperature gas plasmatreatment at a pressure substantially below atmospheric as disclosed inU.S. Pat. No. 5,236,563. The fasteners were made of a homopolymer ofglycolic acid (100% polyglycolide). FIG. 50 depicts the results of shearforce testing that was conducted after the plasma treated fasteners wereplaced in a saline bath simulating an in vivo environment. As can beseen in FIG. 50, at day zero the strength was 2.25 kgf (4.961 lbs),while at day fourteen the strength was 1.59 kgf (3.5 lbs). At day 15,the strength dropped to 1.21 kgf (2.67 lbs) and continued to drop in thesubsequent days.

In some embodiments, the fasteners of the present disclosure may have ahelical configuration. Such helical fasteners are disclosed in U.S. Pat.No. 6,562,051, the contents of which are incorporated by referenceherein. These helical fasteners are depicted in FIG. 42 (including FIGS.42A-F), FIG. 43 (including FIGS. 43A-C), FIG. 44 (including FIGS.44A-C), and FIG. 45. Reference can be made to U.S. Pat. No. 6,562,051for a more detailed explanation of helical fasteners depicted in FIGS.42-45 and their use, including apparatus and/or appliers for theirinsertion into tissue.

Another embodiment of the present disclosure (FIGS. 42 and 42A) isembodied in a resorbable helical fastener 400 which is attached totissue by employing an applier which rotates the fastener 400 intotissue. The dimensions and physical characteristics of the helicalfastener 400 are selected to insure a secure attachment of the fastener400 to tissue.

In a typical embodiment, the fastener 400 is formed into theconfiguration of a continuous helix and may have a depth 402, a diameter404 and a pitch 406 determined by the application. The continuous helixmay be longitudinally collapsible and expandable. The cross-sectionalprofile of the continuous helix is substantially circular in thisembodiment but can be square, rectangular or triangular. In a particularapplication such as mesh anchoring for hernia repair, the pre-formedpitch can be 0.050 inches. However, the pre-formed pitch can vary from 0to a maximum of approximately 3.0 times the coil diameter. In otherembodiments, it is contemplated that the pitch 406 can vary along thelength of the fastener 10 so as to optimize the retaining force of thefastener 400. Moreover, since the continuous helical coil is typicallylongitudinally collapsible and expandable, upon insertion into tissue,the final pitch 408 may be less than or greater than the pre-formedpitch. If the coil is made of rigid construction, as is alsocontemplated, pitch would be made substantially fixed. The diameter inthis embodiment may be 5 mm; however, designs ranging from 1 mm and upare contemplated. In practice, the depth 402 of the fastener 400 must beselected so that the extent of fastener penetration into tissue issufficient to hold the fastener 400 in place.

Moreover, distal end 410 of the fastener 400 is to be configured suchthat a gap 412 exists between the most distal coil 414 (or first coil)of the fastener 400 and its adjacent coil. As may be appreciated fromthe embodiment of FIGS. 42B through 42E, as the fastener 400 is pressedagainst tissue 416, all of the coils substantially collapse except themost distal coil 414, leaving the gap 412 to determine the path thefastener 400 takes as it is rotated into the tissue 416 and moreimportantly, the extent of penetration 418 into the tissue 416 and finalpitch 408 of the fastener 400 in tissue. Although FIG. 42B showssubstantially all of the coils being collapsed, it is to be appreciatedthat, depending upon the applicator utilized to implant the fastener400, fewer coils than all of the coils may be collapsed at any one time.It remains, however, that since the fastener 400 is longitudinallycollapsible and expandable, it is the gap 412 that generally determinesfinal pitch 408. Accordingly, the magnitude of the gap 412 can bevaried, depending upon the application, to achieve the desired finalpitch 408 and penetration 418 in tissue. Thus, the greater the gap 412,upon insertion of the fastener 400 in tissue, the greater thepenetration 418 and final pitch 408 of the fastener 400 in tissue.

In the typical embodiment, the distal end 410 of the helical fastener400 terminates with a point 420. The point 420 may be sharp or bluntdepending upon the tissue to which the fastener 400 will be affixed.Additionally, one or more barbs or a sharp point projecting in reversedirection to point 420 can be added (not shown) to fastener 400 nearpoint 420 to enhance anchoring characteristics of the fastener. Aproximal end 422 of the helical fastener 400 may comprise structurefunctioning to receive and transmit applied longitudinal forces. In thisembodiment, the most proximal coil is formed into a T-bar 424 thatperpendicularly sections the diameter 404 of the fastener 400. Inalternate embodiments, it is also contemplated that the most proximalcoil section the diameter 404 non-perpendicularly or be formed into aspiral 426 existing in a single plane (See FIG. 42F).

In another embodiment of the surgical fastener, the fastener 450 isformed into the configuration of a double helix (See FIGS. 43-43C). Byembodying a double helix, the fastener 450 has increased retentivestrength as well as means to balance the fastener 450 as it is pressedinto tissue. As with the helical fastener 400, the configuration of thedouble helical fastener 450, i.e., the pre-formed pitch and diameter,may be varied for a particular application and a barb may be employed toenhance anchoring in tissue. Moreover, the materials contemplated arethe same as those for the helical fasteners. Further, the double helicalfastener 450 is also longitudinally collapsible and expandable and itsfinal pitch is dependent upon the gap 452 existing between the mostdistal coils 454, 456 of the fastener 450 and their adjacent coils.

Regarding the proximal 458 and distal 460 ends of the double helicalfastener 450, they comprise structure to drive the fastener into tissueas well as tissue piercing structures. The proximal end 458 has aconnector bar 462 sectioning the diameter of the fastener that connectsone helical coil to another and functions to receive and transmitlongitudinal forces. The distal end 460 terminates with two points 464,466 for piercing and facilitating-the implantation of the fastener 450into tissue.

As may be appreciated by comparing FIGS. 43-43C with FIGS. 44-44C, it iscontemplated that the double helical fastener 450 have a full turndesign (FIGS. 43-43C) as well as a half turn design (FIGS. 44-44C). Itis to be understood, however, that the designs having more than one turnand having other increments of turns are contemplated. It is theapplicator that will determine the required number of turns for aspecific fastener 450.

In yet another embodiment of the surgical fastener, as shown in FIG. 45,the double helical fastener 450 is provided with a pivot post 470 havinga pointed terminal end 472. The pivot post 470 of this embodimentoperates to provide the fastener 450 with a stabilizing element so that,as the fastener 450 is being turned, the helical coils cooperativelyenter the tissue.

In another embodiment, the fasteners of the present disclosure may havea clip structure, such as the clip depicted in FIGS. 46-48. FIG. 46shows a first embodiment of a clip fastener according to the presentdisclosure. Clip 500 has a monolithic structure including a distalanchoring rod 502 and a proximal stop bar 504 which are linked viaconnecting rod 506. Distal anchoring rod 502 and proximal stop bar 504extend transversely with respect to connecting rod 506. Anchoring rod502 and proximal stop bar 504 extend on either side of connecting rod506 in such a way as to form an “H”.

Anchoring rod 502 extends in a first direction P of penetration andspacing-apart of an anatomical support 508, in which direction said rodis introduced. The connecting rod 506 extends in a second direction R ofretention in which clip 500 is retained in the flesh, by traction fromthe proximal stop bar 504. Connecting rod 506 is arranged relative toanchoring rod 502 so as to have an inoperative position in which theconnecting rod 506 is arranged along the direction of retention R, and astressed position of penetration, folded back against the anchoring rod502, in which the connecting rod 506 is arranged parallel to thedirection of penetration P. When connecting rod 506 is folded backagainst the anchoring rod 502, the clip is then introduced through theprosthetic part (not shown) and into the flesh, via the distal end 510of the anchoring rod 502, by a push on the proximal end 512 of this samerod 502. When anchoring rod 502 has completely penetrated into thesupport, for example a muscle wall, the angulation at the junction 514between the anchoring rod 502 and the connecting rod 506 acts, at thefirst traction on the clip, in such a way as to bring the connecting rod506 back perpendicular to the anchoring rod 502, in its inoperativeposition. The clip thus is retained between two planes of muscle fibers.At the same time, the proximal stop bar 504 arrests the penetrativedisplacement of the anchoring rod 502, by coming into abutment againstthe prosthetic part (not shown).

The anchoring rod 502 in the first place includes a spacing projection520 acting as a harpoon or barb extending away from the distal end 510in the direction toward the proximal end 512. This spacing projection520 has a surface inclined toward the proximal part of the clip. Theinclination of a surface of the projection 520 makes it possible toensure the spacing apart of the anatomical support, and also to displacethe bending stress, exerted by the prosthetic tissue and the muscle wallon connecting rod 506, further in the direction of the proximal stop bar504, that is to say higher up on the connecting rod 506, as isrepresented in FIG. 46. The elevation of the bending stress point,caused by the projection, allows the connecting rod 506 to align itselfin a substantially parallel manner to the direction of penetration P,without excessively stressing the junction between the anchoring rod 502and the connecting rod 506.

Still referring to FIG. 46, the connecting rod 506 is inclined in a part530 relative to the direction of penetration P of the anchoring rod 502,for example at 45°. Moreover, the connecting rod 506 has a bend 540 andextends in another part 550 from the latter toward the stop bar 504, byforming a substantially right angle therewith, in such a way that thestop bar 504 remains substantially parallel to the anchoring rod 502.

In accordance with FIGS. 47 and 48, and according to a second embodimentof the invention, the clip 500 has, as before, a monolithic structure,and comprises a distal anchoring rod 502 in the anatomical support, aproximal stop bar 504 relative to the prosthetic part, and a connectingrod 506 made in one piece linking the distal anchoring rod 502 and theproximal stop bar 504. As before, the connecting rod 506 is arrangedrelative to the distal anchoring rod 502 so as to determine at least twopositions of this connecting rod 506, namely: an inoperative position inwhich the connecting rod 506 is arranged along a first direction R; anda stressed position in which the connecting rod 506 is folded back alonga second direction P, corresponding to the direction of penetration intothe anatomical support of the distal anchoring rod 502, and this againstthe latter.

According to the present disclosure, in the inoperative position of theconnecting rod 506, the first direction R is inclined relative to thesecond direction P, parallel or identical to that of the anchoring rod502, and this at an angle for example equal to about 45°.

The connecting rod 506 joins the distal anchoring rod 502 at anintermediate point 514 of the latter, for example at the center.

As has been described with reference to FIG. 46, the distal anchoringrod 502 includes at least one spacing projection 520, having the form ofa barb or harpoon, provided in the direction P, extending away from thedistal end 510 in the direction toward the proximal end 512 of thedistal anchoring rod 502.

The connecting rod 506 joins the proximal stop bar 504 at anintermediate point 540 of the latter, for example at the center.

The proximal bar 504 has a larger cross section than that of the distalanchoring rod 502. The connecting rod 506 has an intermediate crosssection between those of the proximal stop bar 504 and of the distalanchoring element 502, respectively.

In the inoperative position of the connecting rod 506, corresponding tothe configuration of the clip before its use, this connecting rod, theproximal stop bar 504 and the distal anchoring rod 502 are arrangedsubstantially in the same plane. The stop bar 504 and the anchoring rod502 are arranged substantially parallel to one another, with theconnecting rod 506 in an inclined or oblique position relative to thestop bar 504 and to the anchoring rod 502.

Methods for repairing tissue with the fasteners of the presentdisclosure are also provided. As noted above, the surgical fasteners ofthe present disclosure may be utilized in a hernial repair method,wherein a surgical mesh is secured in place over a hernia repair site byimbedding the surgical fasteners in to body tissue through the surgicalmesh. In addition, fasteners of the present disclosure may be utilizedto attach one tissue to another including, but not limited to, attachingtissue to a ligament.

Desirably, resorbable screw fastener 10 may be delivered within anendoscopic 5 mm-diameter shaft of a fastener applier capable of firingmultiple fasteners. Components of an applier that may be used in thefiring of resorbable screw fasteners is shown and described in U.S. Pat.No. 5,830,221, the entire disclosure of which is incorporated herein byreference.

Referring now to FIGS. 5 and 6, a fastener applier for applyingresorbable screw fasteners 10 is shown generally as fastener applier100. Fastener applier 100 generally includes a proximal housing portion112, which may be formed as two separate housing halves 112 a and 112 band a handle portion 114 extending from housing 112. A trigger 116 ismovably mounted to housing 112. Trigger 116 may be pivotally connectedto housing 112 with a free end of trigger 116 spaced from a free end ofhandle portion 114. This arrangement provides an ergonomic advantage andpositive secure control of trigger 116 and fastener applier 100.Fastener applier 100 also includes an elongated tubular portion 118extending distally from housing 112. The elongated tubular portion 118is provided to retain a plurality of screw fasteners 10 for applicationto body tissue. Elongated tubular portion 118 is dimensioned to fitthrough conventional endoscopic tubes or cannula structures insertedthrough small incisions in the body. In general, manipulation of controltrigger 116 results in ejection of screw fasteners 10, one by one, outof elongated tubular portion 118 and into body tissue.

With continued reference to FIG. 6, operation of housing portion 112 offastener applier 100 is described. In an initial or starting position,trigger 116 is biased away from handle 114 due to the force of returnspring 115. As shown, teeth 117 of gear portion 121 of trigger 116 areengaged with teeth 119 of trigger gear 123. As trigger 116 is squeezed,teeth 117 engage teeth 119 of trigger gear 123 to rotate driver gear151, which, in turn, rotates a first bevel gear 153 which, in turn,rotates a bevel drive gear 155 and ultimately cylindrical driver 144,fastener retainer 142 and pilot 140 (as seen in FIG. 8). Reference maybe made to U.S. Pat. No. 5,830,221, previously incorporated herein byreference, for a detailed discussion of the operation of housing portion112 of fastener applier 100.

Referring to FIGS. 7-8, elongated tubular portion 118 includes an outertube 136, defining a longitudinal axis “X1” and housing a cylindricaldriver 144. Cylindrical driver 144 generally includes a longitudinallyextending pilot 140, and a cylindrical fastener retainer 142 extendingalong the length of cylindrical driver 144. Fastener retainer 142 isconfigured to receive a plurality of screw fasteners 10 and pilot 140therein, such that upon rotation of cylindrical driver 144, screwfasteners 10 and pilot 140 are similarly rotated. A plurality of screwfasteners 10 may be arranged in a series longitudinally along the lengthof a distal portion of cylindrical driver 144. Each screw fastener 10 ispositionable within fastener retainer 142 of cylindrical driver 144.

Cylindrical driver 144 includes a pair of opposed resilient fingers ortabs 144 a extending from a distal-most end thereof. Each resilientfinger 144 a includes a distal tip 143 a angled and/or otherwiseoriented toward the longitudinal “X1” axis. As seen in FIG. 8, resilientfingers 144 a of cylindrical driver 144 hold or pinch a distal-mostscrew fastener 10 a in position ready for application. In particular,distal tip 143 a of each resilient finger 144 a of cylindrical driver144 is seatable in or receivable in respective slots 28 formed in headportion 14 of screw fastener 10 (see for instance FIG. 1). In operation,cylindrical driver 144 functions to engage a plurality of fasteners andto facilitate turning and driving/advancing of screw fasteners 10 intotissue.

Outer tube 136 may additionally be provided with a crenellated distaltip 136 a for engaging mesh overlying the surgical site in order tomaintain the mesh firmly in position and prevent the mesh from thrustingor otherwise spinning or bunching while resorbable screw fastener 10 istorqued and driven through the mesh. Crenellated distal tip 136 a, ofouter tube 136, may be of various geometric shapes and dimensions,(e.g., serrated, saw-toothed, etc.), or may be omitted completely.

Pilot 140 functions as a guide to aid in the insertion of screw fastener10 into tissue. Pilot 140 includes a sharpened distal tip 140 a fortapping the mesh and underlying target tissue prior to insertion ofscrew fastener 10. Distal tip 140 a of pilot 140 is shown with an angledtip. In an alternative embodiment, distal tip 140 a of pilot 140 may beof various geometries. Referring to FIGS. 9-10, retaining feature 148,provided on pilot 140, holds a distal-most screw fastener 10 a in placeas will be described below. In a loaded position, fastener applier 100includes at least one screw fastener 10 disposed in or retained infastener retainer 142 such that pilot 140 extends through cannulatedopening 18 of screw fastener 10. As explained above, slots 28 of headportion 14 of screw fastener 10 are engaged by respective tips 143 a offingers 144 a of cylindrical driver 144. Tips 143 a of fingers 144 a ofcylindrical driver 144 are configured and dimensioned to engage and/orbe received in respective slots 28 formed in head portion 14 of screwfastener 10.

A method of inserting resorbable screw fastener 10, using fastenerapplier 100, will now be discussed. Referring to FIGS. 5, 6 and 9-17,distal tip 136 a of outer tube 136 is initially placed against the meshand/or the target tissue. Advantageously, crenellated tip 136 a of outertube 136 securely engages the mesh and helps to prevent movement of themesh relative to the tissue. The user then pushes distal tip 136 a ofouter tube 136 against the target mesh or tissue. In so doing, a spring(not shown) is compressed allowing outer tube 136 to retract proximally,in the direction of arrow “A” (see FIG. 9), and thus unlocking a triggerlock (not shown).

As a safety feature, as seen in FIG. 10, pilot 140 remains within outertube 136 even when outer tube 136 is fully retracted. This safetyfeature prevents accidental contact or pricking with distal tip 140 a ofpilot 140.

Referring now to FIGS. 6, 11 and 17, with outer tube 136 in the fullyretracted position, fastener applier 100 is capable of firing screwfastener 10 therefrom. To drive and/or expel fastener(s) 10 fromfastener applier 100, trigger 116 is drawn toward handle 114 against thebias of return spring 115. As trigger 116 is moved, teeth 117 on gearportions 121 of trigger 116 engage and rotate teeth 119 of trigger gear123 clockwise, ultimately causing cylindrical driver 144, fastenerretainer 142 and pilot 140 to be driven (axially in the direction ofarrow “B”) and rotated (about the longitudinal “X1” axis) until pilot140 extends beyond distal tip 136 a of outer tube 136 of fastenerapplier 100, as shown in FIG. 11. In one embodiment, pilot 140 extendsbeyond distal tip 136 a of outer tube 136 by an amount approximatelyequal to 3 mm. Feed spring 145 acts on a plunger 147 to bias plunger 147against the proximal-most screw fastener and maintain a force in thedistal direction on the column of screw fasteners 10 disposed withinfastener retainer 142.

As shown in FIG. 12 and as will be discussed in greater detail below,once pilot 140 has stopped moving distally, cylindrical driver 144 andfastener retainer 142 continue to be driven and rotated distally untilhead portion 14 of a distal-most resorbable screw fastener 10 a issubstantially in line with distal tip 136 a of outer tube 136 thuspreventing insertion of distal-most screw fastener 10 a beyond distaltip 136 a of outer tube 136. As shown in FIG. 12, cylindrical driver 144drives and rotates distal-most screw fastener 10 a completely over andbeyond retaining feature 148 of pilot 140. Additionally, retainingfeature 148 acts as a stop to the distal advancement of an adjacentresorbable screw fastener 10 b, adjacent distal-most screw fastener 10a, until adjacent screw fastener 10 b is engaged and advanced bycylindrical driver 144.

Retaining feature 148 may be in the form of a C-ring, compressibleO-ring, a crimp or bump in the cannulated lumen 18 (see FIG. 15A) or thelike, wherein retaining feature 148 has an initial dimension which isgreater than the dimension of cannulated lumen 18 of screw fastener 10.Accordingly, when distal-most screw fastener 10 a initially engages orcontacts retaining feature 148, since retaining feature 148 is sized tobe larger than cannulated lumen 18, distal-most screw fastener 10 a isprevented from passing. However, as the force being applied todistal-most screw fastener 10 a is increased, retaining feature 148 iscaused to be squeezed into cannulated lumen 18 as distal-most fastener10 a is advanced. Distal-most fastener 10 a is forced entirely acrossretaining feature 148 such that the retaining feature passes throughcannulated lumen 18 and exits a proximal end thereof. The column ofscrew fasteners, behind distal-most fastener 10 a is then distallyadvanced by the force of feed spring 145. However, the force of feedspring 145 is not great enough to cause retaining feature 148 to besqueezed into the next screw fastener. Accordingly, retaining feature148 prevents the distal advancement of the column of screw fasteners.

Once trigger 116 has been completely depressed and distal-most screwfastener 10 a is driven through the mesh and into the tissue, the userreleases trigger 116 and a two stage release cycle begins. Referring toFIG. 13, while fastener retainer 142 remains fixed in place, cylindricaldriver 144 is retracted in a proximal direction (e.g., in the directionof arrow “C”). Cylindrical driver 144 is not rotated and drawn in aproximal direction so that distal-most fastener 10 a is not unscrewed.As cylindrical driver 144 is retracted resilient fingers 144 a deflector cam radially outward as resilient fingers 144 a slide over thetapered surface of slots 28 a to disengage slots 28 a of head portion 14a of distal-most screw fastener 10 a and release distal-most screwfastener 10 a. In addition, as cylindrical driver 144 is retractedresilient fingers 144 a are cammed radially outward by theirinter-engagement with fastener retainer 142. Cylindrical driver 144 maybe retracted until a distal-most tip of resilient fingers 144 a issubstantially aligned with a distal-most edge of fastener retainer 142.

Referring now to FIG. 14, pilot 140 is proximally retracted until pilot140 is disposed within outer tube 136 such that distal tip 140 a ofpilot 140 is not longer exposed. Additionally, cylindrical driver 144and fastener retainer 142 are proximally retracted until tips 143 a ofresilient fingers 144 a of cylindrical driver 144 are aligned with slots28 b formed in head portion 14 b of adjacent screw fastener 10 b. In analternative embodiment, cylindrical driver 144 and pilot 140 may retractindependently of one another or simultaneously.

Referring now to FIG. 15, while screw fastener 10 b is maintained inposition by retaining feature 148, fastener retainer 142 is proximallyretracted, to its starting position, as shown in FIG. 8, so that tips143 a of resilient fingers 144 a of cylindrical driver 144 return totheir un-deflected position and engage slots 28 b of head portion 14 bof adjacent screw fastener 10 b. Since fastener retainer 142 has alonger stroke to return to its starting position as compared tocylindrical driver 144 resilient fingers 144 a of cylindrical driver 144flex back down and engage adjacent screw fastener 10 b. Referring toFIG. 16, outer tube 136 is returned to its starting position, as shownin FIGS. 9 and 17. In alternative embodiments, distal movement of outertube 136 to its starting position can be accompanied by an audibleand/or tactile response heard/felt by the end user. In alternativeembodiments cylindrical driver 144 and fastener retainer 142 canproximally retract together.

In an embodiment, housing 112 may be fabricated to have a reusablehandle portion 114 and trigger 116 that can be re-sterilized, and adisposable elongated tubular portion 118. Thus, upon discharge of allthe screw fasteners 10 elongated tubular portion 118 would be discardedand replaced, housing portion 112 would be sterilized and reused up to alimited number of procedures.

In other embodiments, revolving means to cause cylindrical driver 144 torotate may include a single knob connected to a rotator which can beturned by hand. Additionally, the revolving means may include a rack andgear structure or a set of beveled gears.

FIGS. 18, 18A and 18B present another possible embodiment of theresorbable screw fastener. Screw fastener 200 is similar to screwfastener 10 and will only be discussed in detail to the extent necessaryto identify differences in construction and/or operation. In oneembodiment, body portion 212 of screw fastener 200 has a uniformdistance along at least a portion of, desirably along its entire, lengthwhich is equal to inner distance “D2”. Also, distance “D1” of bodyportion 212 may be tapered from a narrow, blunt distal end 220 to alarger proximal end where it transitions into the outside diameter ofproximal head portion 214 to increase torque strength. The gradual taperalong body portion 212 allows a small footprint of screw fastener 200when entering the mesh, and growing radially outward along the length ofbody portion 212 for better rates of resorption into the body and thentransitions into the outside diameter of head portion 214 to help resisttorque. In addition, slots 228, formed in head portion 214 are parallelto the longitudinal axis “X” axis and extend the entire thickness ofhead portion 214.

Discussion of other fastener appliers which may be utilized withfasteners herein, especially screw fasteners, include those disclosed inInternational Application PCT/US04/18702, (especially FIGS. 19-36thereof), the contents of which are incorporated by reference herein.

With reference to FIGS. 19-21, an end effector for engagement with adistal end of elongated tubular portion 118 of fastener applier 100, tobe used for the application of screw fasteners 10 or 200 or forretaining screw fasteners 10 or 200, is generally designated as 202. Endeffector 202 may take the form of a disposable loading unit (DLU) orsingle use loading unit (SULU) which retains a load of fasteners 10 or200 therein, and which may be disposed of or replaced or may besterilized, re-loaded and reused.

Referring initially to FIGS. 19-21, end effector 202 includes an outertube 236, defining longitudinal axis “X2” and housing an inner tubeassembly 238 for retaining screw fasteners 200 therein, a cam spiraldriver 244 supported on the distal end of tubular portion 118, a pin 254and a cam spiral sub-assembly 248 disposed in inner tube assembly 238and operatively connected to cam spiral drive 244.

End effector 202 is attached to or formed integral with the distal endof elongated tubular portion 118 of fastener applier 100 such that whencontrol trigger 116 of fastener applier 100 is drawn toward handle 114,cam spiral driver 244 rotates (similar to the rotation of cylindricaldriver 144 described above). Cam spiral sub-assembly 248 includes ahelical thread 248 a, which mates with and receives a pin 246 of camspiral driver 244 so that when cam spiral driver 244 rotates, cam spiralsub-assembly 248 rotates and translates, as discussed in detailhereinbelow.

Referring to FIGS. 22 and 23, cam spiral sub-assembly 248 will bediscussed in detail. Cam spiral sub-assembly 248 includes a cam spiral250 having a proximal end 250 a defining a helical thread 248 a, pilot240 extending longitudinally from a distal end 250 b of cam spiral 250,and a fastener retainer 242 operatively supported on distal end 250 b ofcam spiral 250. Cam spiral sub-assembly 248 is assembled in such amanner that upon rotation of cam spiral 250, pilot 240 and fastenerretainer 242 are similarly rotated. In alternative embodiments, camspiral sub -assembly 248 may be fabricated as a single part/component.Fastener retainer 242 may include a pair of opposed longitudinallyextending rails 242 a which act as retainers or guides for screwfasteners 200. A distal end 243 a of rails 242 a will also act as adriver for screw fasteners 200, as will be described hereinbelow.Desirably, a distal end 240 a of pilot 240 extends distally of distalend 243 a of rails 242 a and fastener retainer 242. A pin 254 (see forinstance FIG. 21) is received in and extends radially from a slot 250 cformed in cam spiral 250.

A seen in FIGS. 24-27, cam spiral sub-assembly 248 further includes afeed spring 245 and a screw fastener pusher 247, each disposed on pilot240 and within fastener retainer 242. As shown in FIGS. 25-27, rails 242a of fastener retainer 242 orients screw fasteners 200 by engagingrespective slots 228 in head portion 214 of screw fastener 200.Desirably, feed spring 245 is disposed between screw fastener pusher 247and cam spiral 250. As such, feed spring 245 biases pusher 247 in adistal direction.

Multiple screw fasteners 200 may be retained in or operativelyassociated with cam spiral sub-assembly 248, for example, one(1) as seenin FIG. 25, two (2) as seen in FIG. 26, or three (3) as seen in FIG. 27.While one to three screw fasteners 200 are shown in FIGS. 25-27, it isunderstood that the present device may be used with or may accommodateany number of screw fasteners 200.

Referring now to FIG. 28, in an alternate embodiment or additionally,inner tube sub-assembly 238 includes a cylindrical body 260, a torquering 262 operatively connected to a distal end 260 a thereof, and aretaining ring 264 operatively connected to torque ring 262. Cylindricalbody 260, includes a transversely oriented rotational slot 260 b formedtherein for slideably receiving pin 254 extending from cam spiral 250.Rotational slot 260 b limits the movement of pin 254 and, in turn, therotation of cam spiral driver 244. Rotational slot 260 b may be sized tolimit the rotation to about 90 degrees. With continued reference to FIG.28, torque ring 262 includes a pair of diametrically opposed engagementfeatures 262 a extending radially inward therefrom. Engagement features262 a are desirably sized to mate with corresponding slots 228 of headportion 214 of screw fastener 200. Retaining ring 264 includes two pairof diametrically opposed tabs 264 a, 264 b extending radially inwardtherefrom. Tabs 264 a, 264 b may be offset by about 90 degrees relativeto one another. Desirably, one pair of tabs 264 a is axially alignedwith engagement features 262 a of torque ring 262. Tabs 264 a, 264 bhold distal screw fastener 200 in place and prevent feed spring 245 ofcam spiral sub-assembly 248 from driving all the internal screwfasteners 200 out from the instrument in one rapid fire sequence.

Inner tube sub-assembly 238 may be constructed from several differentcomponents mounted or otherwise operatively connected to one another toform a unitary inner tube sub-assembly 238 or may be manufactured as asingle component.

Referring now to FIGS. 29 and 30, inner tube sub-assembly 238 is shownoperatively associated with (e.g., rotatably supported on) cam spiralsub-assembly 248. As described above, pin 254 extends through rotationalslot 260 b of inner tube sub-assembly 238. Accordingly, inner tubesub-assembly 238 and cam spiral sub-assembly 248 act as one unit whencam spiral sub -assembly 248 is activated, as will be described ingreater detail below.

In FIG. 29, inner tube subassembly 238 is shown in a first position withrespect to cam spiral sub-assembly 248 and with pin 254 located at oneend of rotational slot 260. In FIG. 30, inner tube sub-assembly is shownin a second position with respect to cam spiral sub-assembly 248 andwith pin 254 located at an opposite end of rotational slot 260.

Turning now to FIGS. 31-36, a method of inserting resorbable screwfastener 200 or 10 will be discussed. Referring to FIGS. 32 and 33, adistal tip 236 a (shown crenellated) of outer tube 236 is initiallyplaced against the mesh and/or the target tissue. In so doing, distaltip 236 a of outer tube 236 helps to maintain outer tube 236 firmlyconnected to the mesh and keeps the mesh taught.

Next, the trigger of the fastener applier is actuated (e.g., squeezed)to rotate cam spiral driver 244 and to rotate and translate cam spiralsub-assembly 248 and inner tube sub-assembly 238. Holding outer tube 236in a stationary position, a distal-most screw fastener 200 a is advanceddistally as shown in FIGS. 34 and 35. In particular, as cam spiralsub-assembly 248 is rotating and translating to drive distal-most screwfastener 200 a forward, inner tube sub -assembly 238 rotates distal-mostscrew fastener 200 a.

As seen in FIG. 36, cam spiral sub-assembly 248 (see FIG. 34) will drivedistal screw fastener 200 a an amount sufficient to push distal-mostscrew fastener 200 a beyond tabs 264 b of retaining ring 264 (see FIG.28) and thus releasing distal-most screw fastener 200 a from theremainder of the fastener applier.

Desirably, when the trigger of the fastener applier is released, allinternal sub-assemblies retract and reorient themselves, thus allowingfeed spring 245 to advance the next screw fastener into torque ring 254.

Turning now to FIGS. 37 and 38, another possible embodiment of theresorbable screw fastener, is shown generally as 300. Screw fastener 300is similar to screw fastener 10 and will only be discussed in detail tothe extent necessary to identify differences in construction and/oroperation.

Screw fastener 300 includes a body portion 312 defining a longitudinalaxis “X” and a substantially circular head portion 314 disposed on aproximal end of body portion 312. Body portion 312 includes a helicalthread 316 extending along a length thereof, and terminates in a distalend 320. In the present embodiment, helical thread 316 is tapered totangency at the distal end for ease of insertion purposes. The proximalend of helical thread 316 stops before a distal surface of head portion314 to create gap 316 c in which the mesh (not shown) may be received.

Distal end 320 of body portion 312 defines a distal surface 320 a whichis angled with respect to the “X” axis by an angle Θ. In one embodiment,angle Θ of distal surface 320 a is from about 5° to about 15° withrespect to an axis “Y” which is orthogonal to the “X” axis. In yetanother embodiment, angle Θ is about 9°. Further, body portion 312includes a center shaft 313 extending along a length thereof. In oneembodiment, center shaft 313 is tapered to have a smaller distal end anda larger proximal end in order to increase the ease of insertion ofscrew fastener 300.

With continued reference to FIGS. 37 and 38, head portion 314 includesdriver receiving recesses or structure, in the form of slots 328, formedin an outer radial surface of head portion 314. Slots 328 are configuredto transmit torque to screw fastener 300. In one embodiment, a pair ofdiametrically opposed slots 328 are formed in head portion 314. Eachslot 328 may be parallel to the longitudinal “X” axis, and extendthrough a distal surface 314 a and a proximal surface 314 b of headportion 314. Slots 328 extend the entire length of screw fastener 300 todefine corresponding slots 328 a-328 d formed in helical thread 316.

In one embodiment, head portion 314 has a low profile, i.e., headportion 314 has a length “L2” which is about 1.5 mm and a distance ofabout 3.81 mm. Also, body portion 312 may have a length “L1” which isabout 5.0 mm. As such, the overall length “L” of screw 300 is about 6.5mm.

Alternatively or additionally, it is envisioned that a torquetransmitting feature may be provided on slots 328, in the form ofshoulders 326, the torque transmitting feature allowing for screwfastener 300 to be rotated.

Distal surface 314 a may also be angled as shown with respect to the “X”axis by an angle Φ. In one embodiment, angle Φ of distal surface 314 ais from about 5° to about 15° with respect to an axis “Y” which isorthogonal to the “X” axis. In yet another embodiment, angle Φ is about9°. The angle of distal surface 314 a is provided to help with theremoval of screw fastener 300 in the event that screw fastener 300 needsto be removed from the surgical site.

A space or gap 316 c may be provided between a proximal thread run-outand distal surface 314 a of head portion 314. Gap 316 c allows for thesurgical mesh to rest therein. It is envisioned that the pitch of thread316 may be larger or smaller depending on the particular surgicalprocedure.

As seen in FIG. 37, each slot 328 a-328 d includes a radiused distal orleading edge 329 a and a radiused proximal or trailing edge 329 b.Radiused leading edge 329 a and radiused trailing edge 329 b help tofacilitate insertion of and removal of screw fastener 300 into and fromthe surgical site.

From the foregoing, it will be appreciated that the screw fastener andfastener applier of the present invention cooperate to securely attach afastener with high retentive surface area, to tissue, from onedirection, through the utilization of a fastener applier having asimpler design. It is also to be appreciated that the present inventionmay be utilized in a number of applications including ligating tissue,hernia mesh repair, bladder neck suspension, arthroscopic knee surgery,and in conjunction with implant drug delivery systems or proceduresinvolving positioning of surgical or implantable devices in patients.

While several particular forms of the invention have been illustratedand described, it will also be apparent that various modifications canbe made without departing form the spirit and scope of the invention.

Thus, it should be understood that various changes in form, detail andapplication of the present invention may be made without departing formthe spirit and scope of the invention.

What is claimed is:
 1. A resorbable screw fastener, comprising: a bodyportion defining a longitudinal axis and having a proximal end and adistal end, the distal end having a distal surface extendingnon-perpendicularly relative to the longitudinal axis, the body portionhaving a helical thread formed thereon, the helical thread defining asubstantially flattened surface formed in an outermost diameter of thehelical thread; and an unthreaded head portion disposed at the proximalend of the body portion and defining a longitudinal axis, the headportion having a proximal end and a distal end, the distal end of thehead portion having a distal surface extending non-perpendicularlyrelative to the longitudinal axis, the unthreaded head portion includinga substantially flattened surface formed in an outermost diameterthereof, wherein the substantially flattened surface of the unthreadedhead portion is in radial registration with the substantially flattenedsurface formed in an outermost diameter of the helical thread, whereinthe substantially flattened surface formed in the outermost diameter ofthe helical thread projects partially radially inward from the outermostdiameter of the helical thread.
 2. The resorbable screw fastener ofclaim 1, wherein the head portion further includes a driver receivingstructure defining a slot formed in an outer radial side surface of thehead portion, the driver receiving structure being configured forreceiving both a linear and a rotational force.
 3. The resorbable screwfastener of claim 1, wherein said body portion includes a center shaftthat is tapered from a narrow distal end to a larger proximal end. 4.The resorbable screw fastener of claim 1, wherein said distal end of thebody portion is blunt.
 5. The resorbable screw fastener of claim 1,wherein the helical thread includes a proximal surface defining a landthat is substantially perpendicular to the longitudinal axis.
 6. Theresorbable screw fastener of claim 1, wherein a diameter of the headportion is about 3.8 mm.
 7. The resorbable screw fastener of claim 1,wherein a height of the head portion is about 1.5 mm.
 8. The resorbablescrew fastener of claim 1, wherein a length of the body portion is about5 mm.
 9. The resorbable screw fastener of claim 1, further including acentral lumen extending through an entire length of the body portion.10. A resorbable screw fastener, comprising: a body portion defining alongitudinal axis and having a proximal end and a distal end, the distalend having a distal surface extending non-perpendicularly relative tothe longitudinal axis, the body portion having a helical thread formedthereon, at least a portion of the helical thread including a recessformed in an outer radial edge thereof; and an unthreaded head portiondisposed at the proximal end of the body portion and defining alongitudinal axis, the head portion having a proximal end and a distalend, the distal end of the head portion having a distal surfaceextending non-perpendicularly relative to the longitudinal axis, theunthreaded head portion having a driver receiving structure formedthereon, wherein the driver receiving structure comprises a recessformed in the outer radial edge of the unthreaded head portion, therecess formed in the unthreaded head portion being substantially inradial registration with the recess formed in the helical thread. 11.The resorbable screw fastener of claim 10, wherein the recess formed inthe head portion and the recess formed in the helical thread are planar.12. The resorbable screw fastener of claim 10, wherein the recess formedin the head portion and the recess formed in the helical thread areflattened.
 13. The resorbable screw fastener of claim 10, wherein therecess formed in the head portion and the recess formed in the helicalthread are slots.
 14. The resorbable screw fastener of claim 10, whereinthe recess formed in the head portion is configured to transmit torque.15. The resorbable screw fastener of claim 10, wherein the recess formedin the head portion and the recess formed in the helical thread are eachconfigured to transmit torque.
 16. The resorbable screw fastener ofclaim 10, wherein the head portion further comprises a plurality ofrecesses formed in an outer radial edge thereof.
 17. The resorbablescrew fastener of claim 16, wherein the helical thread further comprisesa plurality of recess formed in an outer radial edge thereof.
 18. Theresorbable screw fastener of claim 17, wherein at least two of therecesses formed in the head portion are substantially in radialregistration with corresponding recesses formed in the helical thread.19. The resorbable screw fastener of claim 10, wherein the resorbablescrew fastener is formed from a bioresorbable polymer.
 20. Theresorbable screw fastener of claim 10, wherein absorption of theresorbable screw fastener is nearly complete at approximately 12 monthspost implantation.